The commoners who married royalty

Princess Lilian's romance with Prince Bertil became one of Sweden's best-known love stories

Despite her Welsh background and fairytale life, the late Princess Lilian of Sweden was not a household name in the UK. She was also not the first commoner to marry royalty. The BBC looks at others, including the Duchess of Cambridge.

For centuries, royal families had sought "equal marriages" for the monarch and those in the line of succession but now it is not so unusual for princes and princesses to marry commoners.

Born Lilian Davies in Swansea in August 1915, the model was already married when she met Prince Bertil of Sweden in London in 1943. The couple fell in love but due to objections from the prince's father they only married 30 years later.

Prince William and Kate Middleton

Kate Middleton's family tree was put under the spotlight ahead of her wedding to Prince William

The Duchess of Cambridge is now one of the most famous commoners to become part of a monarchy.

There was vast media interest in the duchess's background prior to her 2011 wedding to Prince William, second in line to the British throne.

The duchess had a distinctly middle-class background - she grew up in Bucklebury, in Berkshire, where her parents, Michael and Carole Middleton, run a mail-order business selling toys and games for children's parties. Her parents met while they were working for British Airways - he was a flight dispatcher and she was an air stewardess.

The eldest of three children, the duchess was educated at the exclusive Marlborough College in Wiltshire. She met Prince William while they were studying at St Andrews University in Fife.

Prince Frederik of Denmark and Mary Elizabeth Donaldson

Crown Prince Frederik with his wife and children on a skiing holiday in 2013

The royal couple met in a Sydney bar - The Slip Inn - during the 2000 Summer Olympics. At the time, Australian Ms Donaldson was unaware of his royal status as heir to the throne.

They were married in May 2004 and have four children.

Before she became Crown Princess of Denmark, Ms Donaldson was an advertising executive-turned-estate agent.

Tasmania-born Ms Donaldson is the youngest daughter of John Donaldson, a maths professor and Henrietta Donaldson, who died in 1997. Her stepmother is British author Susan Moody, the principal nom de plume of Susan Elizabeth Horwood.

Prince Felipe of Spain and Letizia Ortiz Rocasolano

Prince Felipe and Princess Letizia have two daughters

When Letizia Ortiz Rocasolano married Prince Felipe in 2004, she become the first commoner in Spanish history to be in line to become queen.

She was a well-known TV presenter and the pair met when she was covering an oil slick along the Galicia shoreline in 2002.

She had worked as a journalist for ABC newspaper, the state news agency EFE and local channel CNN+.

They have two daughters together. She had been married previously but Spain's Catholic Church did not oppose her wedding to Prince Felipe because her first wedding was not held in a church.

Crown Princess Victoria of Sweden and Daniel Westling

The couple have a daughter called Princess Estelle

Crown Princess Victoria, heir to the throne, married her former fitness trainer Daniel Westling in 2010. Gym owner Mr Westling, now known as Prince Daniel, first met the princess in 2001.

They announced their engagement eight years later and they were married in 2010. The couple's daughter Estelle, second in line to the throne after her mother, was born in February 2012.

Olof Daniel Westling grew up in a middle-class family in the village of Ockelbo in central Sweden. His mother worked as a clerk at the Swedish post office and his father was a manager at a municipal social services centre.

King Abdullah II and Queen Rania of Jordan

Queen Rania has a prominent profile, at home and abroad

Queen Rania of Jordan is one of the most visible first ladies in the Arab world, known for her glamour and charitable causes.

She met her future husband, who was a prince at that time, at a dinner party in January 1993.

Two months later, they announced their engagement. They now have four children.

Before her marriage, Queen Rania earned a degree in business administration from the American University in Cairo and worked for Citibank and Apple.

A doctor's daughter, she was born in Kuwait in 1970 to a family of Palestinian origin.

Prince Albert II of Monaco and Charlene Wittstock

The marriage of Prince Albert and Charlene Wittstock in 2011 was clouded by rumours

Ms Wittstock, now Her Serene Highness Princess Charlene, married Prince Albert II of Monaco in 2011.

The former South African swimmer met the prince at a swimming event in Monaco in 2000. They officially debuted as a couple at the 2006 Winter Olympic Games in Turin, Italy.

The wedding was clouded by press reports about the couple's relationship, suggesting that Ms Wittstock had come close to returning to South Africa.

Ms Wittstock was born in Zimbabwe's second city of Bulawayo, moving to South Africa with her family at the age of 12.

She represented South Africa at the Commonwealth Games before competing at the 2000 Sydney Olympics as part of the women's medley relay team.

Prince Albert II, 53, has been the ruler of Monaco since the death of his father, Prince Rainier III, in 2005. His mother was royalty of a different sort - the American film star Grace Kelly.

Emperor Akihito and Empress Michiko of Japan

Traditionalists were opposed to Emperor Akihito's choice of wife

Michiko Shoda, the daughter of a prominent industrial and academic family, was the first commoner to marry into the Japanese imperial family in modern times.

Crown Prince Akihito broke another tradition by choosing his bride himself.

Ms Shoda met the then heir to the throne at a tennis match in the summer of 1957. They married two years later and have three children.

An English Literature graduate, she also attended courses at Harvard and Oxford.

Her husband ascended to the throne after the death of his father in 1989.